Field of the Disclosure
Embodiments of the present invention relate to an organic light emitting display device, and more particularly, to a top emission type organic light emitting display device, and a method of manufacturing the same.
Discussion of the Related Art
An organic light emitting display (OLED) device, which is a self light emitting display device, has advantages of low power consumption, rapid response speed, high emission efficiency, high luminance and wide viewing angle.
According to a direction of light emitted from an organic light emitting device, the OLED device may be largely classified into a top emission type and a bottom emission type. In case of the bottom emission type, a circuit device is disposed between an emitting layer and an image displaying surface, whereby an aperture ratio may be lowered due to the circuit device. Meanwhile, in case of the top emission type, a circuit device is not disposed between an emitting layer and an image displaying surface, whereby an aperture ratio may be improved.
FIG. 1 is a cross sectional view of a related art top emission type OLED device.
As shown in FIG. 1, a thin film transistor layer (T) including an active layer 11, a gate insulating film 12, a gate electrode 13, an insulating interlayer 14, a source electrode 15 and a drain electrode 16 is provided on an active area (AA) of a substrate 10, and then a passivation layer 20 and a planarization layer 30 are sequentially provided on the thin film transistor layer (T).
Also, an anode electrode 40 and an auxiliary electrode 50 are provided on the planarization layer 30. The auxiliary electrode 50 is provided to lower a resistance of a cathode electrode 80 to be explained later.
On the anode electrode 40 and the auxiliary electrode 50, a bank 60 is provided to define a pixel region. Also, an organic emitting layer 70 is provided in the pixel region defined by the bank 60, and the cathode electrode 80 is provided on the organic emitting layer 70.
In case of the top emission type, light emitted from the organic emitting layer 70 passes through the cathode electrode 80. In this reason, the cathode electrode 80 is formed of a transparent conductive material, which causes the increase of resistance therein. In order to lower the resistance of the cathode electrode 80, the cathode electrode 80 is connected with the auxiliary electrode 50.
On a pad area (PA) of the substrate 10, there are the gate insulating film 12 and the insulating interlayer 14. A signal pad 90 is provided on the insulating interlayer 14, and the passivation layer 20 is provided on the signal pad 90. A contact hole is provided in the passivation layer 20 so that the signal pad 90 is exposed to the external via the contact hole. A pad electrode 95 is provided on the passivation layer 20. The pad electrode 95 is connected with the signal pad 90 exposed via the contact hole.
However, the related art top emission type organic light emitting display device may have the following disadvantages.
The pad electrode 95 is manufactured for a process of manufacturing the anode electrode 40, whereby the pad electrode 95 is formed of the same material as that of the anode electrode 40. In this case, the anode electrode 40 is formed of a metal material with good reflectance, for example, argentums (Ag) so as to reflect the light emitted from the organic emitting layer 70 toward the cathode electrode 80. However, the metal material with good reflectance, for example, argentums (Ag) is vulnerable to corrosion. A lateral side of the anode electrode 40 is covered by the bank 60, and an upper surface of the anode electrode 40 is covered by the organic emitting layer 70, so that it is possible to prevent the anode electrode 40 from being corroded. However, the pad electrode 95 is exposed to the external, and connected with an external driver, whereby the pad electrode 95 is corroded.
Further, in order to prevent the corrosion, an upper surface of the pad electrode 95 may be formed of a corrosion-resistant material. Even in this case, it is difficult to prevent a lateral side of the pad electrode 95 from being corroded.